Updated README.md with information about usage with expo

I added a chapter about usage with expo. This was previously  not included in the documentation and I felt the need to add it in to make sure people safe some time.

Author: JorritKeijzer

README.md

@@ -15,6 +15,7 @@ For more information about **ConnectionService** on Android, please see [Android
 - [Demo](#Demo)
 - [Installation](#Installation)
 - [Usage](#Usage)
+  - [Expo](#Usage-with-Expo)
   - [Constants](#Constants)
   - [Android Self Managed](#Android-Self-Managed-Mode)
   - [API](#Api)
@@ -155,6 +156,10 @@ Alternative on iOS you can perform setup in `AppDelegate.m`. Doing this allows c
 
 You can alternatively just call `setSettings()` with the same option as `setup()` to define only your settings.
 
+# Usage with Expo
+
+To use this library with Expo, you will need to create a development build. Expo does not support running native modules directly. For information on how to create and run a development build, visit: [Create a development build - Expo Documentation](https://docs.expo.dev/develop/development-builds/create-a-build/). You can use and test this library with a development build installed on your physical device (iOS and Android). 
+
 # Constants
 
 To make passing the right integer into methods easier, there are constants that are exported from the module.
@@ -1108,6 +1113,7 @@ class RNCallKeepExample extends React.Component {
 }
 ```
 
+
 ## Receiving a call when the application is not reachable.
 
 In some case your application can be unreachable :